Saw Dust Ash as Partial Replacement for Cement in the Production of Sandcrete Hollow Blocks

This study investigates the use of Saw Dust Ash (SDA) as partial replacement for ordinary Portland cement (OPC) in sandcrete blocks. Some units of sandcrete hollow blocks were produced by partially replacing the cement content with 5% to 25% by weight of SDA, using vibrating block moulding machine. Sandcrete blocks without SDA serve as the control. The blocks produced were tested to determine their density, compressive strength and water absorption rate. The results indicated that compressive strength of sandcrete hollow blocks at 28 days are 2.16N/mm 2 , 1.94N/mm 2 , 1.64N/mm 2 , 1.59N/mm 2 ,1.39N/mm 2 , and 1.25N/mm 2 for Control, 5%, 10%, 15%, 20% and 25% SDA contents respectively. At 56 days, the compressive strength of blocks with 5% and 10% SDA replacement are 2.33N/mm 2 and 2.04N/mm 2 respectively, both of which surpassed the required standard of 2.00N/mm 2 specified by the National Building Code (2006) for non-load bearing walls. It was concluded that only sandcrete blocks with up to 10% SDA replacement can be used for non-load bearing walls.